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Biomedical subjects

W A Gay

Publications and source records attributed to W A Gay.

At least 91 records · Page 5Linked to original sources
PubMed1978

The postpericardiotomy syndrome then and now.

The postpericardiotomy syndrome is a febrile illness with pericardial and pleural reaction that either persists or appears beyond the 1st postoperative week. We believe that it begins in the 1st week after intrapericardial cardiac surgery, and that clinical signs of illness correlate with appearance of AHA and with significant rise in titer to AVA. Our present working hypothesis is that myocardial damage with bleeding into the pericardial sac at the time of surgery combines with concurrently acquired or reactivated viral illness to set the stage for the syndrome. The immune response is triggered by viral invasion of traumatized myocardium and an immune response is mounted, not against autologous myocardium per se but against the neo-antigen, the virus-infected myocardium. The illness is self-limited. It sometimes recurs but it seems to leave no sequelae other than the bad memory of a painful postoperative complication that prolonged hospitalization and delayed the realization of the full benefits of that heart operation.

Antibodies, Viral↗
PubMed1978

Evaluation of methods for the quantification of experimental myocardial infarction.

Several invasive and noninvasive techniques used in determining the size of experimental myocardial infarction were evaluated after acute ligation of the left anterior descending (LAD) coronary artery in ten dogs. Systemic blood pressure, left ventricular end-diastolic pressure (LVEDP), and heart rate did not change significantly for up to 24 hours after coronary occlusion. Left ventricular wall motion abnormalities were detected by left ventriculography in the distribution of the LAD but these changes did not correlate well with the infarct weight determined at autopsy. On the other hand, the number of epicardial sites with ST-segment elevation of greater than or equal to 2 mm (mean 15.1 sites +/- 0.6 SEM) and the infarct area as measured by 99mTc-glucoheptonate (TcGH) myocardial imaging (15.7 sq cm +/- 0.6) did correlate strongly with the infarct weight (16.8 g +/- 0.7) determined by the nitroblue tetrazolium (NBT) technique (r = 0.91). TcGH myocardial scintigraphy and epicardial ST-segment mapping allowed early and accurate quantification of experimental myocardial infarcts ranging from less than 1 g to 28 g.

Animals↗
PubMed1978

Aortic dissection beginning in the abdomen.

Two cases of aortic dissection beginning in the abdominal aorta are presented, and the angiographic and surgical principles are discussed. Every effort must be made to identify the sites of all intimal tears at aortography and to excise or oversew these sites at surgery; otherwise, dissection may continue. If an intimal tear cannot be identified at aortography, we recommend initial conservative therapy unless the patient's clinical condition forces emergency surgery.

Aged↗
PubMed1978

Hypertension following coronary artery bypass graft surgery: comparison of hemodynamic responses to nitroprusside, phentolamine, and converting enzyme inhibitor.

Sustained systemic hypertension (mean arterial pressure 119 +/- 4 mm Hg) developed in 39 patients undergoing coronary artery bypass graft (CABG) surgery. In groups of patients with comparable mean arterial pressure, left ventricular filling pressure, heart rate, and cardiac output, treatment with sodium nitroprusside (NP) in 20 patients, phentolamine (PH) in 10 patients and nonapeptide converting enzyme inhibitor (CEI) in nine patients uniformly lowered mean arterial pressure by 26, 21, and 20%, respectively. Cardiac output increased during NP (5.7 +/- 0.1 to 6.4 +/- 0.3 L/min, P < 0.0005) and after CEI (5.7 +/- 0.4 to 7.4 +/- 0.5 L/min, P < 0.0005) but not after PH (5.7 +/- 0.3 to 5.9 +/- 0.3 L/min, P > 0.05). Left ventricular filling pressure decreased in all groups (P < 0.005), but heart rate increased during NP (91.3 +/- 2.4 to 98.4 +/- 2.2 beats/min, P < 0.0005 and after PH (95.5 +/- 2.1 to 99.2 +/- 3.0, P < 0.005), while it was unchanged after CEI P > 0.05). Of the nine patients with CABG hypertension who received CEI, seven exhibited a mean decrease in arterial pressure of 18.5 +/- 3.4%, while in the remaining two patients, mean arterial pressure was decreased only 3.4%. In the former, the pretreatment mean plasma renin activity (PRA) was 7.5 +/- 2.4 ng/ml/hr, while in the latter, mean PRA was 1.3 ng/ml/hr.

Adult↗
PubMed1977

Surgical treatment of endocardial cushion defects.

A recent surgical experience with the spectrum of atrioventricular (A-V) canal is reviewed. Twenty-five patients underwent surgery for the partial and complete from of this defect in the 4 years from 1971 through 1974. Sixteen had a partial defect, two a transitional defect and seven complete A-V canal. The characteristic murmurs accompanied by cardiac enlargement, pulmonay overcirculation and left axis deviation in the electrocardiogram were sufficient for diagnosis in most cases. Cardiac catherization was performed in all patients preoperatively and in 11 postoperatively. The operative approach, including a double patch modification of the usual repair for complete canal, is considered. Definitive repair, rather than pulmonary arterial banding, is advocated regardless of the patient's age. The operative mortality rate is low in patients with the ostium primum type of defect but is related to associated intracardiac anomalies in those with the complete form of the defect. Residual mitral insufficiency is a common finding after surgical repair of both partial (75 percent) and complete (100 percent) A-V canal. Although no patient in the series died of florid mitral regurgitation, the long-range effects of this complication may lead to mitral valve replacement.

Adolescent↗
PubMed1977

Systemic hypertension associated with coronary artery bypass surgery. Predisposing factors, hemodynamic characteristics, humoral profile, and treatment.

Systemic hypertension occurs in more than one third of patients having coronary artery bypass graft (CABG) operations. This report describes our studies in 100 consecutive patients undergoing CABG. We found that certain preoperative clinical, angiographic, and biochemical factors predispose to the development of perioperative hypertension. These included a well-documented history of hypertension, an elevated blood pressure the day prior to operation, greater than 50 percent obstruction of the left main coronary artery, and increased levels of dopamine beta hydroxylase (DBH). The hemodynamic pattern of perioperative hypertension was that of an increased systemic vascular resistance which was associated with increased levels of plasma catecholamines and plasma renin activity (PRA). Nitroprusside was shown to be effective in managing CABG hypertension, although other, more specific therapy may be preferable.

Adult↗
PubMed1977

Physiologic observations of the heart six months after ischemic normothermic cardioplegia.

The late effects of normothermic ischemic cardioplegia were studied in four experimental groups of dogs subjected to intervals of aortic cross-clamping during cardiopulmonary bypass. Groups which had zero, 20, 30, or 40 minutes of aortic cross-clamping, respectively, were studied 6 months later for cardiac performance and morphology. The immediate operative mortality rate of animals subjected to 40 minutes of ischemia was 65 percent, compared to 22 percent in controls. There were no late deaths in any group Compliance, histology, biochemical determination of deoxyribonucleic acid: ribonucleic acid, and Vmax determinations after cross-clamping revealed no differences between the experimental groups. Open chest isovolumetric contraction curves showed decreased experimental groups. Open chest isovolumetric contraction curves showed decreased function in the 40 minute ischemia group at the extreme levels of cardiac stress. These results suggest that under the conditions of this study normothermic cardiac ischemia of greater than 30 minutes in duration results in a high initial mortality rate (65 percent) and leads to compromise of cardiac function under stress in the late postoperative period.

Animals↗
PubMed1976

Multiple aortic aneurysms in relapsing polychondritis.

A patient with relapsing polychondritis and thoracic and abdominal aortic aneurysms is described. The aortic changes were due to aortitis, which primarily involved the media, with increased vascularization, perviascular infiltration of mononuclear cells, increased amounts of collagen and decreased amounts of elastic tissue and sulfated acid mucopolysaccharides. Aortic aneurysms frequently occur in relapsing polychondritis; they are usually in the ascending aorta but may be multiple and involve the abdominal aorta; involvement of the ascending aorta results in aortic regurgitation and left ventricular failure, and involvement of the abdominal aorta may be clinically silent and result in fatal rupture.

Adult↗
PubMed1975

Potassium-induced cardioplegia.

Cardioplegia induced with an osmotically balanced solution of high potassium concentration appears to lower the oxygen requirements of the heart, slows high-energy phosphate depletion to some extent, and is associated with increased survival in prolonged normothermic ischemia. To date no obvious detrimental effects have been observed from injecting this solution.

Animals↗
PubMed1975

The protective effects of induced hyperkalemia during total circulatory arrest.

Three groups of adult mongrel dogs were subjected to 15 minutes of toal circulatory arrest. One group was infused with one liter of Krebs-Hensleit solution and kept normothermic, one group was infused similarly and their body temperature was lowered to 10 to 15 degrees C., and the third group was kept normothermic and infused with hyperkalemic solution. Adenosine triphosphate (ATP) and creatine phosphate levels in the brain during and after the ischemic period were not significantly different in the three groups and glycogen levels tended to remain higher in the hypothermic group. None of the normothermic dogs survived, but all of the hypothermic and hyperkalemic animals survived and were grossly normal. These data indicate that hyperkalemai does offer some protection to the brain during periods of circulatory arrest. It also appears that survival and persistence of brain function do not correlate necessarily with levels of high energy compounds in the brain.

Adenosine Diphosphate↗